Shulou(Shulou.com)11/24 Report--

The original title: "Today is World Wi-Fi Day!" "

Many people don't know that June 20 every year is actually World Wi-Fi Day:

This special anniversary is determined by the Wireless Broadband Alliance (Wireless Broadband Alliance) and is strongly supported by organizations such as the Internet cities Advisory Council (CCAB).

Wireless Broadband Alliance, which coincides with the 20th anniversary this year.

World Wi-Fi Day is set up to encourage government departments, operators and service providers to provide Internet connectivity to everyone around the world to help bridge the global digital divide.

As you may not know, in today's highly developed network, there are still nearly 3 billion people around the world who do not have access to the Internet, most of them from developing countries and poor rural areas.

The picture is from the United Nations Children's Fund (UNICEF) Wi-Fi, an important and ubiquitous communication technology that has helped many people access the Internet. It is not only an indispensable part of our life, but also a powerful tool to promote economic development and social progress.

Next, let's review the birth of Wi-Fi:

A brief History of █ Wi-Fi in 1896, the Italian Galilmo Marconi realized the first radio communication in human history. Since then, mankind has opened the door to the radio world.

After the birth of Galilmo Marconi (1874-1937) wireless telegraphy, it not only greatly improved people's communication efficiency, but also broke the limitation of communication distance.

The telegrapher who is "listening" to the telegram is developing in step with the wireless telegraphy service, and there is also the radio broadcasting service. This is another important application of wireless technology.

The first radio station in the world with the increasing number of radio and radio stations on the earth, wireless interference is becoming more and more serious.

In this case, the government began to intervene to regulate wireless broadcasting and strictly restrict the use of radio frequencies.

This is the origin of the spectrum authorization system.

In the 1970s, cellular mobile communications began to rise, and also did not escape the spectrum licensing system.

At that time, in the United States, the person responsible for managing and authorizing the spectrum was FCC (Federal Communications Commission).

After the FCC logo entered the 1980s, with the rapid development of microcircuit and digital signal processing technology, wireless technology is advancing by leaps and bounds, new wireless devices are constantly invented, and new mobile communication standards are also emerging. However, limited by the spectrum licensing system, the research and development of these new equipment and new technologies are seriously restricted.

At this time, a key figure appeared-- he was Michael Marcus (later called "Wi-Fi Godfather").

Marcus was an ordinary engineer at FCC at the time.

One day, he made a suggestion to his leader: he hoped to stipulate some unauthorized spectrum, open it to the industry, and appropriately increase the transmission power of these unauthorized spectrum devices so that they can cover a range of tens to hundreds of meters. If this is done, it will help to encourage science and technology enterprises to make more innovation and bring greater economic benefits.

FCC adopted his suggestion and solicited opinions from all walks of life. However, I got totally irresponsible feedback:

As long as you don't occupy my frequency band, you can play whatever you want!

Yes, at that time, the frequency band resources were already so crowded that no one wanted to release the frequency band they had.

In the end, FCC can only release three unpopular "junk bands" from the only free bands. These bands are the ISM bands that we often talk about now.

These bands are mainly open to industry, science and medicine, and belong to Free License (free license), so they are also called "unauthorized spectrum".

In terms of equipment transmission power, FCC stipulates that the transmission power of these new unlicensed frequency bands can reach 1W.

No one would have thought that it was this 1W that made today's Wi-Fi, Bluetooth, ZigBee and other short-distance communication technologies.

At that time, in order to avoid interference between devices, FCC required these new unlicensed band products to use spread spectrum technology.

The so-called spread spectrum technology means that the bandwidth used to transmit information is much larger than the bandwidth of the information itself, spread spectrum modulation is carried out by spread spectrum coding at the transmitter, and information is received by correlation demodulation technology at the receiver. Spread spectrum technology was first used in the military field, which has the characteristics of high reliability, high confidentiality and not easy to be disturbed.

After the introduction of the new FCC regulations, it has been widely welcomed by the industry. However, at a time when everyone is immersed in development, new problems arise--

There is no uniform standard in the whole industry.

At that time, many wireless product equipment manufacturers developed their own special equipment, no matter who, and the devices of different manufacturers were not compatible at all.

In 1988, the American company NCR wanted to use unauthorized frequency bands to make wireless cash registers (NCR was the first company in the world to make mechanical and electric cash registers, which was later acquired by AT&T). So I called Victor Hayes, an engineer in their R & D department, and asked him what to do about it.

Victor HayesVictor Hayes is very forward-looking and believes that there must be a unified standard first. Victor Hayes then approached IEEE in conjunction with Bruce Tuch, another engineer at Bell Labs, in the hope of establishing a common set of unauthorized spectrum standards.

So in the early 1990s, IEEE, the Institute of Electrical and Electronic Engineers, IEEE established the famous 802.11 working Group, chaired by Victor Hayes.

Meanwhile, in 1991, NCR's engineering team and its joint venture partner AT&T developed WaveLAN technology in Neuwegein, the Netherlands. This technology is considered to be the prototype of Wi-Fi.

So, is NCR the inventor of Wi-Fi? It's not.

While NCR was messing with WaveLAN, CSIRO, a research institute of the Australian government, invented a wireless network technology. The specific inventors are John Sullivan (John O'Sullivan) of the University of Sydney and his team.

In Dr John O'Sullivan1996, they successfully applied for a technology patent in the United States, the patent number is US Patent Number 5487069. (later, a lawsuit was fought for the patent. )

In 1999, when IEEE officially defined the 802.11 standard, it selected and recognized that the wireless network technology invented by CSIRO is the best wireless network technology in the world, so it was adopted as the core technical standard of Wi-Fi.

Finally, the standard versions of IEEE802.11, 802.11b (working in 2.4GHz band) and 802.11a (working in 5.8GHz band), were approved in December 1999 and January 2000, respectively.

While the working group was busy setting standards, six companies, Intersil, 3Com, Nokia, Aironet, Symbol and Lucent, formed the Wireless Ethernet compatibility Alliance (Wireless Ethernet Compatibility Alliance, abbreviated as WECA).

The main purpose of the establishment of WECA is to certify the compatibility of products from different manufacturers and to achieve the interoperability of equipment from different manufacturers.

After the establishment of the alliance, in order to facilitate marketing, we discussed plans to change a loud name, such as "WECA compatible", "IEEE802.11b compatible" and so on. However, this stagnant term is difficult for people to blurt out.

In order to do this, WECA also consulted brand experts, who gave them a lot of advice, such as "FlankSpeed", "DragonFly" and so on.

Finally, the name "Wi-Fi" won.

It is called "Wi-Fi" because it sounds a bit like "HiFi", which is easy to suggest that CD players from different manufacturers can be compatible with any power amplifier device. Later, some people said that "Wi-Fi" is the abbreviation of "wireless fidelity". In fact, this is just what people imagined later.

In October 2002, WECA officially changed its name to Wi-Fi Alliance (Wi-Fi Alliance).

The technology has been standardized and the stage name is available. What should we do now?

Hold your thighs.

No matter how good your technology is, someone should be willing to use it, and there should be equipment vendors to support it.

So Lucent, a member of the Wi-Fi alliance, approached Apple in the hope that their products would introduce Wi-Fi.

Apple was so arrogant that they told Lucent: if the price of your wireless adapter can be reduced to less than $100, we will design a Wi-Fi slot in the laptop.

Lucent agreed.

In July 1999, Apple introduced the Wi-Fi for the first time in its new generation of iBook laptops, but it was not standard, it was just an option.

Jobs demonstrated the "wireless" magic of the iBook G3, which he named "AirPort" but it was this "optional" that quickly attracted other computer manufacturers to follow.

Not only hardware manufacturers have followed Wi-Fi, but Microsoft's Windows XP operating system has also added support for Wi-Fi (users can connect wirelessly without installing third-party drivers or software).

Since then, the scope of use of Wi-Fi has been expanding, from individual to family, from family to public places, into every one of our lives.

At this time, the IEEE802.11 working group readjusted the IEEE802.11 protocol standard and launched a new physical layer standard IEEE802.11g. It uses a more advanced spread spectrum technology, called orthogonal Frequency Division Multiplexing (OFDM) modulation technology, and its rate can reach 54Mbps in the 2.4GHz band.

Later, there are 802.11n, 802.11ac, 802.11ax and so on.

The trajectory of 802.11 is precisely because naming methods such as 802.11a / b / n / g / ac / ax are so confusing that they can't easily tell the order, so IEEE decided to start with 802.11ax and name them digitally.

And 802.11ax is our mainstream Wi-Fi 6 now.

After more than 20 years of development, the transmission speed of Wi-Fi 6 is 873 times higher than that of the first generation Wi-Fi.

Now, Wi-Fi has entered a new stage. Wi-Fi 7, which has attracted a lot of attention, is coming into our lives. Its speed will reach an amazing 40Gbps above.

It has to be said that Wi-Fi is a very successful wireless communication technology, which has changed our lives to a great extent.

Facing the fully digital and intelligent human society, how long will Wi-Fi technology accompany us? Will it have more innovation?

Let's wait and see!

(full text)

References:

Https://mp.weixin.qq.com/s/Mq5IkeE36qnjMMJmNUFOiw

Http://biz.zol.com.cn/638/6382835.html

Https://www.zhihu.com/question/23539623/answer/109747299

Http://xinwen.eastday.com/a/180310182443182.html

This article comes from the official account of Wechat: fresh Jujube classroom (ID:xzclasscom), author: Xiaozaojun

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